Aerobic Exercise for Alzheimer's Disease Prevention in At-Risk Middle-Aged Adults

This is a 26-week aerobic exercise intervention. The primary mode of training is treadmill walking, with the initial speed and duration calibrated to each participant's baseline aerobic capacity. Participants will train 3-4 days per week with the goal of attaining 150+ minutes of exercise per week by the seventh week. Exercise will be set between 50-60% of maximum heart rate reserve for weeks 1-4, 60-70% for weeks 5-8, and 70-80% for weeks 9-26. Exercise duration will be approximately 15-20 minutes per session during the first week and then increase by 5 minutes each week until a duration of approximately 38-50 minutes per session is reached. Each training session will begin with a 5-minute warm-up and end with a 5-minute recovery period.